Assessment of Membrane Processing Plant for Whey Concentration in Ovine Dairy Industry

Decrease of pollution potential, volume reduction and recovery of valuable components are the key aspects that are concerned with the economical convenience of whey processing technologies. Among membrane applications, reverse osmosis (RO) can be effectively used for achieving the separation of salt, protein and and lactose from whey and deproteinized whey (scotta). This study reports the operational results of a polymeric membrane continuous system, based on RO technology, recently installed in a sheep cheese factory which produces a total volume of 22 millions liters of scotta per year. Energy requirements and economical performances have been also evaluated in comparison to the previous management practices. Plant processing capacity, with a pressure level set at 35 bars, was about 10,000 L h-1, while the volume concentration ratio (VCR) was on average 2.8. In comparison to raw scotta, the concentration process decreased the costs associated to transport and refrigeration, while the selling price of retentate was higher. While the RO treatment of scotta required an average cost of 0.008 € L-1, the use ofthis technology generated a positive income of about 70,000 € per year. Permeate resulting from membrane processing (roughly 63% of the initial whey volume) which COD=700-800 mg L-1 was much lower than dairy wastewaters, could be further processed by RO to produce and recycle purified water.